Process of smelting auriferous antimony ores.



m. 643,301. Patented Feb. 13, 19cm.I c. c. LUNGRIDGE & G. T. HoLLowAY.

PROCESS 0F SMELTING AUI-'HFERUSv ANTIMNY URES.

(Application led Aug.` 15, 1896.) (No Model.) 2 Sheets-Sheet M m m m NUi.

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No. 643,30l. Patented Fab., L3, |900.` C. C. LNGRIDGE &. G. T. HOLLWAY.l

PROCESS 0F SMELTING AURIFERUUS ANTIMONY GRES.

(Application filed Aug. 15, 1896.)

2 Sheets-Sheet 2.

{No Model.)

OEOIL CLEMENT LONGRIDGE, OF LEIGH, AND GEORGE THOMAS HOLLOWAY, OFLONDON, ENGLAND.

PROCESS QF SlVlELTING AURIFEROUS ANTIMONY CRES.

SPECIFICATION forming part ofLetters Patent No. 643,301, dated February13, 1900. Application led August l5, 1896. Serial No. 602,902. (Nospecimens.)

T all whom it may concern:4

Beit known that we, CEOIL CLEMENT LONG- RIDGE, consulting and miningengineer, residing at Leigh, in the county of Essex, and GEoRGE THOMASHoLLowAY, analytical and consulting chemist, residing at 57 ChanceryLane, London, in the county of Middlesex,

England, citizens of Great Britain, have invented certain new and usefulImprovements ro in Plants and Processes for SmeltingAuriferous AntimonyOrcs, of which the following is a specification.

Our invention relates to an improved process of smeltingant-imony oreswhereby also gold, if present, can be extracted, and for this purpose weemploy a continuous system of furnaces or chambers, preferablygas-fired, whereby a constant temperature and a reducing atmosphere canbe better maintained.

In the accompanying drawings, Figure 1 is a plan of the generalarrangement of furnaces or chambers so employed, while Figs. 2 and 3 arerespectively sections on the lines ZJ b and a a, Fig. l. Fig. 4 is asectional elevation on lines C D of Fig. 5; Fig. 5, a sectional plan online A B of Fig. 4 of an alternative mixing-furnace.

The general arrangement as illustrated consists of a liquating-furnaceA, a reducing-furnace C, a refining-furnace D, and a starringfurnace Eor furnace in which crude metallic antimony is purified from sulfur andother impurities; but refining and starring, if desired, may beconducted in the same furnaces. When it is desired to extract gold fromthe ore, a mixing or gold-extracting furnace B is interposed between theliquating furnace A and the reducing-furnace C and in this the gold isextracted from the liquated suld by the method hereinafter described.The furnacesare vin communication with flues for the passage of thefurnace-gases, so that the same can at will be led through each furnaceindependently before entering the condensing flue or stack or conductedsuccessively throughout'the series and so effect economy of heat, andthe furnaces may likewise be provided with by-pass valves and flues, sothat the combustion-gases can be led around any furnace 0r furnaces whenrepairs are required or the nature of the operation conducted renders itadvisable.

For the better regulation of the temperature and for independent workingthe furnaces are fitted with direct auxiliary gas-sup- 5 5 ply. Thefurnaces are supplied with the necessary tapping-holes and coveredconduits or launders J for leading the metal from one furnace to theother, as also stirring and sightholes, ore-chutes, doors, duc.

In the actual arrangement illustrated in the drawings it will be seenthat the reducing, reiining, and starringfurnaces C, D, and E areindependently fired from the gas-supply main F and that provision ismade for direct firing of the mixing chamber or furnace B in a branch Ffrom the main supply-pipe F; but the mixing chamber or furnace B may bekept at normal temperature by means of the waste gases from the otherfurnaces C D E, con- 7o ducted through flues H and nozzle H. In thealternative, however, such waste products may be conducted through aby-pass H2 to the liquating-furnace A, a suitable Valve I being providedfor regulation as required. The liquating'fnrnace or chamber A may alsobe fired or kept at normal temperature by the waste gasespassinglthrough the by-pass H2 or, in the alternative, may be tireddirect with gas from t-he main supply-pipe F. A suitable 8o valve isprovided for regulation while the gas is admitted into the furnace at Land passes through the flue K to the chimney-stack. A conduit or launderJ is provided for the purpose of conveying the liquated sulfld or otherore to the mixing-chamber,as illustrated. The antimony suliid is firstreduced to crude metallic antimony by singling in the furnace C-that is,by fusion-with metallic iron, whereby iron sulfid and metallic antimony9o are produced. This-crude metal is then passed by means of a launder Jto the next furnace D for doubling or refining by fusion with liquatedantimony suliid and common salt, whereby the metal is to a great'extentfreed 95 from iron. This partly-refined metal is next treated by f usienin the next` starring-furnace E, to which it is passed through thelaunder J, with a flux commonly used by antimonysmelters under the nameof antimony flux. roo

The starring is a process of purification from sulfur as well as fromiron. A launder N is provided for conveying the gold-laden antimony fromthe mixing-chamber B when such has become sufficiently enriched withgold.

To favor the flow of metal, the furnaces are built on an incline orseries of steps, as illustrated in Fig. 3, the liquating-furnace A beingat the top and the starring-furnace E at the bottom of the series.

The gases of combustion may be made to flow upward, as illustrated, ordownward through the series, according to the position of the stack.

The gold-extracting furnace B is so constructed as to insure completeand continuous mixing of the sultid with the metallic antimony. Wetherefore employ for this purpose either a rotary or an agitatingfurnace or a fixed furnace with a mechanical mixer, a convenient form ofthe latter being a vertical revolving spindle driven by cog, worm,friction, or belt gearing and carrying a fireclay stirrer with orwithout a metal foundation, the same being protected from the action ofthe sulfid. The stirrer may be shaped like the blade of ascrew-propeller.

A rotary furnace B is illustrated in the drawings, which is driven bymeans of gearing Z9 b capable of being operated by manual power, and thefurnace rotates upon rollers b2 b2 and is provided with an interiorlining of refractory material and a series of ribs b3.

A fixed furnace O is illustrated in the drawings, Figs. 4 and 5, whichis built of firebrick upon a foundation S and within a metal encasementT. A stirrer P operates within the furnace O and is mounted at theextremity of a vertically-disposed rotating shaft P, which is held inposition within a bearing upon the top plate U, which is fixed upon thetop of the furnace O. The shaft P is caused to rotate by means ofbeveled gearing Q Q', motion being derived from the shaft R and pulleyR', mounted thereupon, motion being communicated to pulley R' by meansof a rope or belt. The stirrer P is covered with fire-clay and isprovided with holes P2 within each of its blades to augment the intimateadmixture and to facilitate rotation. The liquated ore passes from theliquating-furnaces through a launder J into the extractingfurnace O,while fused metallic antimony is added through the charging-door V5 androtation of the stirrer P is effected, the gas passing up from theconduit V and meeting with a supply of air through the air-admissionaperture V, igniting in the chamber V2 and passing to the interior ofthe furnace 0 and in contact with the ore and antimony, and thencepassing through the conduit V3 away. V4, Fig. 5, shows a lighting andsight hole, while N are launders along which the gold carrying antimonyis withdrawn.

We do not limit ourselves to the use of the gold-extracting furnace inconnection with the series of furnaces for the reduction of antimony',but may use the extracting-furnace alone if it is desired to extract thegold and reduce the sulfid elsewhere, or we can use such series withoutthe extracting-furnace if the gold is not to be extracted.

The furnaces are preferably built to work with prod ucergas from aproducer or plant G, as supplied by the several systems now in use.

Our method of extracting gold from antimony ores and other auriferousproducts when gold is present in a free state and in this form solublein antimony or sulfid of antimony is as follows:

First. The liquated sulfid or other ore of antimony carrying gold freedfrom gangue if present to any notable extent is agitated in any suitablefurnace or receptacle with metallic antimony, which by reason` of thegreater affinity of the metallic antimony for the metallic gold thansulfid of antimony extracts the gold present in the ore.

Second. The liquated suld or other ore of antimony carrying gold istreated with sufficient metallic iron capable of reducing antimonytherefrom, so as to reduce sufficient antimony to extract and retain thegold. The reducing action of the iron may be expressed by the equationThird. B y a combination of the first and second methods the proportionof antimony used for the gold extraction need only form a smallproportion of the sulfid treated; but we preferably employ a quantityequal to fifty per cent. or more of the sulfid treated. The metallicantimony and the sulfid or other ore are intimately and continuouslymixed by mechanical stirring until the extraction is judged to becomplete. The metallic antimony employed is used with successive chargesof ore until it is found sufficiently enriched with gold, when it iswithdrawn from the furnace. The antimony when enriched with gold isheated in one of the furnaces C, D,or E in the presence of an oxidizingatmosphere or in an excess of air, so that the antimony is convertedinto oxid (Sb/,02) according to the following equation:

The antimony oxid passes off as vapor and may be condensed in the finesor elsewhere, and the gold is left behind in the metallic state. Wellknown electrolytic or economical process may be utilized, however, forthe recovery of the gold. It does not appear advisable to enrich theantimony to more than one hundred ounces of gold to the ton.

In describing the methods which we preferably employ for treatingauriferous antimony ores we will refer to the ore known as antimoniteand consisting of the sulfid of antimony carrying free gold, as that isthe most common ore of antimony.

In the case of the first method the ore is liquated and the suliid isrun into the mixing or IOO IOS

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gold-extracting furnace or chamber B, where it is intimately andcontinuously mixed, as before described, with the metallic antimony, sothat the antimony shall come in contact with the maximum amount of thesulfid. When the extraction is judged complete, the suld is removed fromthe furnace or chamber and a freshcharge may be treated.

In treating very rich ores With little or no gangue the liquation mightbe conducted in the extracting furnace or chamber, if desired.

When treating antimonite by the second method, the liquated suld isacted upon by sufficient metallic iron or other suitable reducing agentto reduce sufficient antimonyto combine with the bulk of the gold, and asystem of mixing or agitating is adopted, as in the case of the firstmethod.

As ordinary antimonite will dissolve a proportion of the metallicantimony in the extracting-furnace, and thus reduce the bath, the lossmay be made good bya combination of the first and second methods or byintroducing fresh antimony, as required.

In treating auriferous substances other than ores of antimony We firsttreat the same with fused liquated sulfid of antimony, in which metallicgold is readily soluble, and having thus concentrated the gold in theantimony suld we treat the latter as already described to extract thegold from it. Owing to the small quantity of gold present in auriferousantimony,which averages three and one-half ounces of gold per ton ofore, and therefore only about one-hundredth of one per cent., it hasnever been found possible to find out exactly the state in which itexists. Sometimes it is in the visible metallic state; but in many casesit is probably in the form ofa double sulfid ofV antimony and gold. Itis impossible, therefore, to express the changes which occur during theextraction of the gold by equations. The result is merely an alloy ofgold and antimony, the ore being unaffected except that its containedgold has been removed. It is not perhaps right to say that metallicantimony has a greater afiinity for metallic gold than sulfur. What isthe case is that the metallic antimony has a greater affinity formetallic gold than sulfid of antimony-that is, the ore-and any othersupposition is unwarran table. No doubt when antimony is added to thefused gold sulfid the gold would be liberated and dissolved in theexcess of antimony, the sulfur liberated from the gold combining withits equivalent of antimony; but We have no reason for thinking that thegold is present as sulfid of gold. The simplest way of regarding thematter is to consider the gold as simply dissolved, as salt dissolves inwater.

Having thus described our nventiomwhat we claim as new, and desire tosecure by Letters Patent, iss- A process for the extraction of gold fromauriferous antimony sulfid ores consisting in the fusion of metallicantimony with ore and in the addition of sufficient metallic iron to thefused ore to convert enough antimony suliid to metallic antimony to makegood the loss of metallic antimony due to the solvent action of thesulfid ore and in the intimate admixture of the metallic antimony andsulfid of antimony by mechanical means, so as to effect the extractionof the gold by virtue of the greater affinity of the metallic antimonythan the antimony sulfid for gold and by the greater density of theantimony gold alloy produced, substantially as hereinbefore described.

In witness whereof We have hereunto set our rhands in presence of twowitnesses.

OEOIL CLEMENT LONGRIDGE. GEORGE THOMAS HOLLOWAY.

WVitnesses WILLIAM EVANS, WILLIAM HALL.

